G. 8XERNA. 49 



Hydrocecropis antarctica (Forst.), Bote, Isis, 1844, p. 179. 

 Sternula antarctica {Forst.) ?, Bp. C. ii. xlii. j). 773, no. 141 (1856). 

 Sterna cinerea, EUman, 'Ajoloyid, 1861, p. 7473. 

 Sterna bveviunguis, I'elz. Hcise Novara, Voy. p. 152 (1866 : New 



Zealand, in Vienna Mus.). 

 llydrochelidon hybrida, Finsch, J.f. 0. 1867, p. 347. 



Advlt male m breeding-plumage. Forehead, lores, crown, and 

 nape deep black ; from the gape a broad streak of white passes 

 under the eye and is continued to the nape ; mantle dark pearl- 

 grey ; secondaries very slightly edged with white ; outer primaries 

 with white shafts and pale grey margins to the inner webs : 

 rump white ; tail-feathers dark pearl-grey except the outer pair 

 of feathers, which are nearly white on the upper parts ; under 

 tail-coverts greyish white ; breast and abdomen pearl-grey : bill 

 bright yellow ; iridcs black ; tarsi and toes bright yellow. Total 

 length 12 inches, ciilmcu 1-25, wing 10, tail 4-5-5, depth of fork 

 1*75 at most, tarsus 0'65, middle toe and claw 0-9. 



Female. Similar, with perhaps less prolongation of the outer tail- 

 feathers. 



Adidt in ivinter. The head is probably greyish for a brief period. 



Immature. Similar, with a dark band on the upper wing-coverts, 

 which is retained until after the black head is assumed ; the upper 

 parts dull grey. 



Young. Head ash-grey mottled with black ; upper wing-coverts, 

 inner secondaries, and tail-feathers with subterminal ash-brown 

 markings : bill ochraceous yellow, blackish towards the tip ; feet 

 dull yellow : otherwise like the immature. 



ffab. New Zealand, chiefly the South Island ; once in Norfolk 

 Island. Frequents rivers and plains, and deposits eggs on the 

 bare ground. 



The strongly contrasted white stripe below the eye and the 

 somewhat short and slightly pointed tail doubtless led Gray to place 

 this species in the genus Hydrochelidon ; but it is not a Marsh- 

 Tern, its toes have not indented webs, and it is merely a some- 

 what specialized link in the interesting chain to which the three 

 following species of true Sea-Terns belong. 



a. Ad. St. New Zealand. P. Earl, Esq. [0.]. 



(Type of species.) 



b, c. Ad. St. Port Cooper, South Island, F. Strange, Esq. [C], 



New Zealand. 

 d, c. (S,f. 2 ad. ; Otago, N. Zealand, Sept. Hume Coll. 



k. Ad. sk. Otago, N. Z. H. Saunders Coll. 



I. (S ad. sk. Waimakariri, N. Z., Oct. H. Saunders Coll. 



w. Juv. sk. Cape Campbell, N. Z., 41^ 45' H. Saunders Coll. 



S. lat. 



n. Juv. sk. Wellington, N. Z. H. Saunders Coll. 



0. Ad. sk. Norfolk Island, 28° S. H. Saunders GoU. 



